1. Field of the Invention
The present invention relates generally to a magnetic tape recording/reproducing apparatus, and more particularly, to a digital audio tape recorder (hereinafter xe2x80x9cDATxe2x80x9d) streamer in which a motor rotates a cam gear to put the DAT streamer into one of a plurality of different operating modes.
2. Description of the Related Art
DAT streamers are used as large-capacity external memory back-up devices for computers. The typical DAT streamer is composed of a cam gear rotated by a motor, with a variety of mechanisms activated in response to the rotation of the cam gear so as to put the DAT streamer into a magnetic tape cassette load mode, a tape insert mode, a recording/reproducing mode and the like. Such a configuration requires that the shifting of the operating modes be detected with a high degree of reliability.
An example of a conventional DAT streamer operating mode shift detection device is shown in FIGS. 1A and 1B. As can be appreciated from the drawings, such a device consists of a rotating plate 11 rotating in synchrony with a cam gear. Three leaf spring contacts 12-1, 12-2 and 12-3 are disposed on the rotating plate 11 in such a way as to slide over an electrode pattern 14 of predetermined shape of a circuit board 13, so that a shifting of operating modes is detected by a combination of the output of the contacts 12-1, 12-2 and 12-3.
The operating mode shift detection device described above is a metal contact type. As a result, the reliability of the detection readings is easily affected by the intensity of the pressure of the contact, the quality of the grease, the presence of dirt and dust, and so on. The reliability of the detection readings can be improved by increasing the intensity of the pressure of the contact. However, doing so increases the wear on the electrode pattern 14 and shortens its life.
Accordingly, it is a general object of the present invention to provide an improved and useful magnetic tape recording/reproducing apparatus in which the problems described above are eliminated. Another more specific object of the present invention is to provide a magnetic tape recording/reproducing apparatus capable of detecting an operating mode shift with a high degree of reliability.
The above-described objects of the present invention are achieved by a magnetic tape recording/reproducing apparatus adapted for loading a magnetic tape cassette, comprising:
a magnetic head;
a magnetic tape loading mechanism loading and unloading a magnetic tape cassette and loading and unloading a magnetic tape within the magnetic tape cassette to the magnetic head, the magnetic tape loading mechanism assuming a plurality of operating states; and
an optical detector for optically detecting a shifting of the magnetic tape loading mechanism from one operating state to another operating state.
According to the invention described above, the operating mode shift detection device is a non-contact type. Accordingly, the effect of the presence of dirt and dust on the reliability of the detection readings is much reduced as compared to the contact-type operating mode shift detection device. As a result, the reliability of detection readings can be improved and at the same time the problem of wear on the electrode pattern 14 can be eliminated.
Additionally, the above-described objects of the present invention are also achieved by a magnetic tape recording/reproducing apparatus adapted to load a magnetic tape cassette, comprising:
a magnetic head;
a cam gear rotatably driven by a motor;
a magnetic tape loading mechanism operated by the rotation of the cam gear, the magnetic tape loading mechanism loading and unloading the magnetic tape cassette and loading and unloading a magnetic tape inside the magnetic tape cassette to the magnetic head, the magnetic tape loading mechanism assuming a plurality of operating states;
a rotating member rotating in synchrony with the cam gear and having a plurality of optical detectors;
a switch detecting a loading of the magnetic tape cassette; and
a control circuit detecting a shifting of the magnetic tape loading mechanism from one operating state to another operating state based on an output from the plurality of optical detectors and an output from the switch.
According to the invention described above, by using the output of the switch detecting the loading of the magnetic tape cassette it becomes possible to reduce the number of photosensors to a small number. Accordingly, even a rotating member having a relatively small diameter is adequate to accommodate the optical detectors.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.